In the traditional sense, 'domingo' is not a slang term, but simply the Spanish word for 'Sunday'. However, in some Spanish-speaking regions, it is used as a slang term to describe a person who is seen as lazy or unproductive, presumably because Sundays are typically viewed as days of rest.
Examples
- Spanish: Juan es un verdadero domingo, nunca hace nada productivo.
- English: Juan is a real Sunday, he never does anything productive.